Recent advances in cancer treatment have shown that in order to plan appropriate treatment of cancer and make an accurate prognosis it is necessary to have sensitive methods at one's disposal for detecting the presence of cancer, the type of cancer and its stage, for the purpose of determining its precise localization and its possible spread to other tissues. An accurate diagnosis of cancer can help to reduce the number of deaths from cancer and improve patients' quality of life, as it makes it possible to select the most appropriate treatment (chemotherapy, surgical resection, etc.) and reduce the patient's discomfort by defining the end point of therapeutic treatment.
Prognostic markers supply important information for the treatment and development of cancer in patients. In fact, for the application of systemic adjunctive therapy in the treatment of some types of primary cancers, identification of high-risk and low-risk patients is one of the main aims. Various prognostic markers are known, both classical markers, for example tumor size, state of the lymph nodes, histopathology, state of the steroid receptor, and second-generation markers, for example rate of proliferation, ploidy of the DNA, oncogenes, growth factor receptors and certain glycoproteins, which prove very useful for making therapeutic decisions (McGuire, W. L., Prognostic Factors for Recurrence and Survival, in “Educational Booklet American Society of Clinical Oncology”, 25th Annual Meeting, 89-92 (1989); Contesso et al., Eur. J. Clin. Oncol., 25:403-409 (1989)). Although none of the known prognostic markers fully satisfies the aim of distinguishing between patients of low and high risk, by combining various markers it may be possible to improve the prediction of a patient's prognosis, therefore the search is continuing for new prognostic markers that could be added to those already available to assist in the prognosis of cancer, its progression and the residual disease after treatment. However, just as important as the prognosis of cancer is the diagnosis of possible metastasis in those patients who have already developed cancer, determining the degree of severity of the disease of a subject with cancer, or monitoring the effect of the treatment administered to a subject with cancer.
The genetic elements responsible for the invasion and metastasis of cancer are still unknown. It would therefore be helpful to identify diagnostic markers of invasiveness that could be analyzed in a simple manner.